In a specific application, the product is of the lotion, gel or cream type, for example, for cosmetic use or for pharmaceutical treatments.
Dispensing systems are known which comprises a pump equipped with a tube for supplying the pressurized product on which a pushbutton-type dispensing head is fixed in order to actuate the movement of said tube over a product dispensing/suction stroke.
In particular, the dispensing head can comprise a body having a mounting shaft for said head on the supply tube and a product dispensing channel between said mounting shaft and a dispensing orifice. Thus, by pressing on the body of the dispensing head, the pump is actuated in order to dispense the product through the dispensing orifice in the form of a drop or a continuous stream.
The dispensing orifice can be formed between two longitudinal walls, upper and lower, respectively, which are connected on either side by a lateral wall of which the transverse dimension is smaller than the longitudinal dimension of the longitudinal walls. Thus, the product is dispensed in the form of a layer that has a longitudinal dimension that is greater than its transverse dimension, in particular with a substantially rectangular cross-section.
Around the world, various directives are intended to regulate, control and limit the presence of substances potentially dangerous for human health in cosmetic products in particular. One of them is the European directive REACh (Registration Evaluation and Authorisation of Chemicals). In addition, an environmental tendency is pushing cosmetologists to limit preservatives and even remove them from their formulas, as they often cause allergies or intolerance.
Cosmetic products are therefore becoming increasingly fragile. In particular, they have difficulty withstanding mechanical or thermal stress (for example, causing a phase change), contact with air (for example, causing drying, oxidation), and are easily contaminated by bacteria, yeast and mould.
To fight this contamination, formulators attempt to reinforce the intrinsic preservative activity of their products by adding ingredients having a preservative activity, such as certain essential oils, orange essences, vitamin C, and so on, which are not declared as preservatives. In addition, they limit the free activity of water, which they attempt to keep low (AW<0.6) to limit or eliminate the development of bacteria. Standard NF 29621 describes such means. However, the formulators quickly come up against the limits of such a strategy.
On the other hand, protective dispensing systems are appearing on the market. In particular, systems have been proposed in which the dispensing channel is not very narrow and not very twisted, so as not to subject the product to pressure during its dispensing. So-called “airless” systems have also been proposed, in which air does not enter in order to compensate for the volume of product dispensed, or in which the entering air is filtered through a mesh on the order of 0.2 μm in order to retain bacteria, yeast and mould.
Systems have also been proposed in which the dispensing orifices is self-closing, thereby limiting contact of the product with air between uses. However, this mechanical self-closing, formed at the interface of two often imperfect shapes, cannot guarantee full retention of bacteria, yeast and mould, which are several dozen micrometres in size.